add return None statements

pythonbpf/allocation_pass.py

@@ -5,6 +5,7 @@ from llvmlite import ir
 from dataclasses import dataclass
 from typing import Any
 from pythonbpf.helper import HelperHandlerRegistry
+from .expr import VmlinuxHandlerRegistry
 from pythonbpf.type_deducer import ctypes_to_ir
 
 logger = logging.getLogger(__name__)
@@ -49,6 +50,15 @@ def handle_assign_allocation(builder, stmt, local_sym_tab, structs_sym_tab):
         logger.debug(f"Variable {var_name} already allocated, skipping")
         return
 
+    # When allocating a variable, check if it's a vmlinux struct type
+    if isinstance(stmt.value, ast.Name) and VmlinuxHandlerRegistry.is_vmlinux_struct(
+        stmt.value.id
+    ):
+        # Handle vmlinux struct allocation
+        # This requires more implementation
+        print(stmt.value)
+        pass
+
     # Determine type and allocate based on rval
     if isinstance(rval, ast.Call):
         _allocate_for_call(builder, var_name, rval, local_sym_tab, structs_sym_tab)

pythonbpf/codegen.py

@@ -5,6 +5,8 @@ from .functions import func_proc
 from .maps import maps_proc
 from .structs import structs_proc
 from .vmlinux_parser import vmlinux_proc
+from pythonbpf.vmlinux_parser.vmlinux_exports_handler import VmlinuxHandler
+from .expr import VmlinuxHandlerRegistry
 from .globals_pass import (
     globals_list_creation,
     globals_processing,
@@ -56,10 +58,13 @@ def processor(source_code, filename, module):
         logger.info(f"Found BPF function/struct: {func_node.name}")
 
     vmlinux_symtab = vmlinux_proc(tree, module)
+    if vmlinux_symtab:
+        handler = VmlinuxHandler.initialize(vmlinux_symtab)
+        VmlinuxHandlerRegistry.set_handler(handler)
+
     populate_global_symbol_table(tree, module)
     license_processing(tree, module)
     globals_processing(tree, module)
-    print("DEBUG:", vmlinux_symtab)
     structs_sym_tab = structs_proc(tree, module, bpf_chunks)
     map_sym_tab = maps_proc(tree, module, bpf_chunks)
     func_proc(tree, module, bpf_chunks, map_sym_tab, structs_sym_tab)

pythonbpf/expr/__init__.py

@@ -2,6 +2,7 @@ from .expr_pass import eval_expr, handle_expr, get_operand_value
 from .type_normalization import convert_to_bool, get_base_type_and_depth
 from .ir_ops import deref_to_depth
 from .call_registry import CallHandlerRegistry
+from .vmlinux_registry import VmlinuxHandlerRegistry
 
 __all__ = [
     "eval_expr",
@@ -11,4 +12,5 @@ __all__ = [
     "deref_to_depth",
     "get_operand_value",
     "CallHandlerRegistry",
+    "VmlinuxHandlerRegistry",
 ]

pythonbpf/expr/expr_pass.py

@@ -12,6 +12,7 @@ from .type_normalization import (
     get_base_type_and_depth,
     deref_to_depth,
 )
+from .vmlinux_registry import VmlinuxHandlerRegistry
 
 logger: Logger = logging.getLogger(__name__)
 
@@ -27,8 +28,12 @@ def _handle_name_expr(expr: ast.Name, local_sym_tab: Dict, builder: ir.IRBuilder
         val = builder.load(var)
         return val, local_sym_tab[expr.id].ir_type
     else:
-        logger.info(f"Undefined variable {expr.id}")
-        return None
+        # Check if it's a vmlinux enum/constant
+        vmlinux_result = VmlinuxHandlerRegistry.handle_name(expr.id)
+        if vmlinux_result is not None:
+            return vmlinux_result
+
+        raise SyntaxError(f"Undefined variable {expr.id}")
 
 
 def _handle_constant_expr(module, builder, expr: ast.Constant):
@@ -74,6 +79,13 @@ def _handle_attribute_expr(
                 val = builder.load(gep)
                 field_type = metadata.field_type(attr_name)
                 return val, field_type
+
+        # Try vmlinux handler as fallback
+        vmlinux_result = VmlinuxHandlerRegistry.handle_attribute(
+            expr, local_sym_tab, None, builder
+        )
+        if vmlinux_result is not None:
+            return vmlinux_result
     return None
 
 
@@ -130,7 +142,12 @@ def get_operand_value(
             logger.info(f"var is {var}, base_type is {base_type}, depth is {depth}")
             val = deref_to_depth(func, builder, var, depth)
             return val
-        raise ValueError(f"Undefined variable: {operand.id}")
+        else:
+            # Check if it's a vmlinux enum/constant
+            vmlinux_result = VmlinuxHandlerRegistry.handle_name(operand.id)
+            if vmlinux_result is not None:
+                val, _ = vmlinux_result
+                return val
     elif isinstance(operand, ast.Constant):
         if isinstance(operand.value, int):
             cst = ir.Constant(ir.IntType(64), int(operand.value))
@@ -332,6 +349,7 @@ def _handle_unary_op(
         neg_one = ir.Constant(ir.IntType(64), -1)
         result = builder.mul(operand, neg_one)
         return result, ir.IntType(64)
+    return None
 
 
 # ============================================================================

pythonbpf/expr/vmlinux_registry.py

@@ -0,0 +1,45 @@
+import ast
+
+
+class VmlinuxHandlerRegistry:
+    """Registry for vmlinux handler operations"""
+
+    _handler = None
+
+    @classmethod
+    def set_handler(cls, handler):
+        """Set the vmlinux handler"""
+        cls._handler = handler
+
+    @classmethod
+    def get_handler(cls):
+        """Get the vmlinux handler"""
+        return cls._handler
+
+    @classmethod
+    def handle_name(cls, name):
+        """Try to handle a name as vmlinux enum/constant"""
+        if cls._handler is None:
+            return None
+        return cls._handler.handle_vmlinux_enum(name)
+
+    @classmethod
+    def handle_attribute(cls, expr, local_sym_tab, module, builder):
+        """Try to handle an attribute access as vmlinux struct field"""
+        if cls._handler is None:
+            return None
+
+        if isinstance(expr.value, ast.Name):
+            var_name = expr.value.id
+            field_name = expr.attr
+            return cls._handler.handle_vmlinux_struct_field(
+                var_name, field_name, module, builder, local_sym_tab
+            )
+        return None
+
+    @classmethod
+    def is_vmlinux_struct(cls, name):
+        """Check if a name refers to a vmlinux struct"""
+        if cls._handler is None:
+            return False
+        return cls._handler.is_vmlinux_struct(name)

pythonbpf/functions/functions_pass.py

@@ -311,7 +311,13 @@ def process_stmt(
 
 
 def process_func_body(
-    module, builder, func_node, func, ret_type, map_sym_tab, structs_sym_tab
+    module,
+    builder,
+    func_node,
+    func,
+    ret_type,
+    map_sym_tab,
+    structs_sym_tab,
 ):
     """Process the body of a bpf function"""
     # TODO: A lot.  We just have print -> bpf_trace_printk for now
@@ -384,7 +390,13 @@ def process_bpf_chunk(func_node, module, return_type, map_sym_tab, structs_sym_t
     builder = ir.IRBuilder(block)
 
     process_func_body(
-        module, builder, func_node, func, ret_type, map_sym_tab, structs_sym_tab
+        module,
+        builder,
+        func_node,
+        func,
+        ret_type,
+        map_sym_tab,
+        structs_sym_tab,
     )
     return func
 

pythonbpf/helper/printk_formatter.py

@@ -3,6 +3,7 @@ import logging
 
 from llvmlite import ir
 from pythonbpf.expr import eval_expr, get_base_type_and_depth, deref_to_depth
+from pythonbpf.expr.vmlinux_registry import VmlinuxHandlerRegistry
 
 logger = logging.getLogger(__name__)
 
@@ -108,6 +109,16 @@ def _process_name_in_fval(name_node, fmt_parts, exprs, local_sym_tab):
     if local_sym_tab and name_node.id in local_sym_tab:
         _, var_type, tmp = local_sym_tab[name_node.id]
         _populate_fval(var_type, name_node, fmt_parts, exprs)
+    else:
+        # Try to resolve through vmlinux registry if not in local symbol table
+        result = VmlinuxHandlerRegistry.handle_name(name_node.id)
+        if result:
+            val, var_type = result
+            _populate_fval(var_type, name_node, fmt_parts, exprs)
+        else:
+            raise ValueError(
+                f"Variable '{name_node.id}' not found in symbol table or vmlinux"
+            )
 
 
 def _process_attr_in_fval(attr_node, fmt_parts, exprs, local_sym_tab, struct_sym_tab):

pythonbpf/maps/maps_pass.py

@@ -6,6 +6,8 @@ from llvmlite import ir
 from .maps_utils import MapProcessorRegistry
 from .map_types import BPFMapType
 from .map_debug_info import create_map_debug_info, create_ringbuf_debug_info
+from pythonbpf.expr.vmlinux_registry import VmlinuxHandlerRegistry
+
 
 logger: Logger = logging.getLogger(__name__)
 
@@ -51,7 +53,7 @@ def _parse_map_params(rval, expected_args=None):
     """Parse map parameters from call arguments and keywords."""
 
     params = {}
-
+    handler = VmlinuxHandlerRegistry.get_handler()
     # Parse positional arguments
     if expected_args:
         for i, arg_name in enumerate(expected_args):
@@ -65,7 +67,12 @@ def _parse_map_params(rval, expected_args=None):
     # Parse keyword arguments (override positional)
     for keyword in rval.keywords:
         if isinstance(keyword.value, ast.Name):
-            params[keyword.arg] = keyword.value.id
+            name = keyword.value.id
+            if handler and handler.is_vmlinux_enum(name):
+                result = handler.get_vmlinux_enum_value(name)
+                params[keyword.arg] = result if result is not None else name
+            else:
+                params[keyword.arg] = name
         elif isinstance(keyword.value, ast.Constant):
             params[keyword.arg] = keyword.value.value
 

pythonbpf/vmlinux_parser/import_detector.py

@@ -2,6 +2,7 @@ import ast
 import logging
 import importlib
 import inspect
+import llvmlite.ir as ir
 
 from .assignment_info import AssignmentInfo, AssignmentType
 from .dependency_handler import DependencyHandler
@@ -76,9 +77,28 @@ def detect_import_statement(tree: ast.AST) -> list[tuple[str, ast.ImportFrom]]:
     return vmlinux_imports
 
 
+def bpf_passthrough_gen(module):
+    i32_ty = ir.IntType(32)
+    ptr_ty = ir.PointerType(ir.IntType(8))
+    fnty = ir.FunctionType(ptr_ty, [i32_ty, ptr_ty])
+
+    # Declare the intrinsic
+    passthrough = ir.Function(module, fnty, "llvm.bpf.passthrough.p0.p0")
+
+    # Set function attributes
+    # TODO: the ones commented are supposed to be there but cannot be added due to llvmlite limitations at the moment
+    # passthrough.attributes.add("nofree")
+    # passthrough.attributes.add("nosync")
+    passthrough.attributes.add("nounwind")
+    # passthrough.attributes.add("memory(none)")
+
+    return passthrough
+
+
 def vmlinux_proc(tree: ast.AST, module):
     import_statements = detect_import_statement(tree)
 
+    bpf_passthrough_gen(module)
     # initialise dependency handler
     handler = DependencyHandler()
     # initialise assignment dictionary of name to type
@@ -86,19 +106,19 @@ def vmlinux_proc(tree: ast.AST, module):
 
     if not import_statements:
         logger.info("No vmlinux imports found")
-        return
+        return None
 
     # Import vmlinux module directly
     try:
         vmlinux_mod = importlib.import_module("vmlinux")
     except ImportError:
         logger.warning("Could not import vmlinux module")
-        return
+        return None
 
     source_file = inspect.getsourcefile(vmlinux_mod)
     if source_file is None:
         logger.warning("Cannot find source for vmlinux module")
-        return
+        return None
 
     with open(source_file, "r") as f:
         mod_ast = ast.parse(f.read(), filename=source_file)

pythonbpf/vmlinux_parser/vmlinux_exports_handler.py

@@ -0,0 +1,90 @@
+import logging
+from llvmlite import ir
+
+from pythonbpf.vmlinux_parser.assignment_info import AssignmentType
+
+logger = logging.getLogger(__name__)
+
+
+class VmlinuxHandler:
+    """Handler for vmlinux-related operations"""
+
+    _instance = None
+
+    @classmethod
+    def get_instance(cls):
+        """Get the singleton instance"""
+        if cls._instance is None:
+            logger.warning("VmlinuxHandler used before initialization")
+            return None
+        return cls._instance
+
+    @classmethod
+    def initialize(cls, vmlinux_symtab):
+        """Initialize the handler with vmlinux symbol table"""
+        cls._instance = cls(vmlinux_symtab)
+        return cls._instance
+
+    def __init__(self, vmlinux_symtab):
+        """Initialize with vmlinux symbol table"""
+        self.vmlinux_symtab = vmlinux_symtab
+        logger.info(
+            f"VmlinuxHandler initialized with {len(vmlinux_symtab) if vmlinux_symtab else 0} symbols"
+        )
+
+    def is_vmlinux_enum(self, name):
+        """Check if name is a vmlinux enum constant"""
+        return (
+            name in self.vmlinux_symtab
+            and self.vmlinux_symtab[name]["value_type"] == AssignmentType.CONSTANT
+        )
+
+    def is_vmlinux_struct(self, name):
+        """Check if name is a vmlinux struct"""
+        return (
+            name in self.vmlinux_symtab
+            and self.vmlinux_symtab[name]["value_type"] == AssignmentType.STRUCT
+        )
+
+    def handle_vmlinux_enum(self, name):
+        """Handle vmlinux enum constants by returning LLVM IR constants"""
+        if self.is_vmlinux_enum(name):
+            value = self.vmlinux_symtab[name]["value"]
+            logger.info(f"Resolving vmlinux enum {name} = {value}")
+            return ir.Constant(ir.IntType(64), value), ir.IntType(64)
+        return None
+
+    def get_vmlinux_enum_value(self, name):
+        """Handle vmlinux enum constants by returning LLVM IR constants"""
+        if self.is_vmlinux_enum(name):
+            value = self.vmlinux_symtab[name]["value"]
+            logger.info(f"The value of vmlinux enum {name} = {value}")
+            return value
+        return None
+
+    def handle_vmlinux_struct(self, struct_name, module, builder):
+        """Handle vmlinux struct initializations"""
+        if self.is_vmlinux_struct(struct_name):
+            # TODO: Implement core-specific struct handling
+            # This will be more complex and depends on the BTF information
+            logger.info(f"Handling vmlinux struct {struct_name}")
+            # Return struct type and allocated pointer
+            # This is a stub, actual implementation will be more complex
+            return None
+        return None
+
+    def handle_vmlinux_struct_field(
+        self, struct_var_name, field_name, module, builder, local_sym_tab
+    ):
+        """Handle access to vmlinux struct fields"""
+        # Check if it's a variable of vmlinux struct type
+        if struct_var_name in local_sym_tab:
+            var_info = local_sym_tab[struct_var_name]  # noqa: F841
+            # Need to check if this variable is a vmlinux struct
+            # This will depend on how you track vmlinux struct types in your symbol table
+            logger.info(
+                f"Attempting to access field {field_name} of possible vmlinux struct {struct_var_name}"
+            )
+            # Return pointer to field and field type
+            return None
+        return None

tests/c-form/ex5.bpf.c

@@ -1,25 +0,0 @@
-#define __TARGET_ARCH_arm64
-
-#include "vmlinux.h"
-#include <bpf/bpf_helpers.h>
-#include <bpf/bpf_tracing.h>
-#include <bpf/bpf_core_read.h>
-
-// Map: key = struct request*, value = u64 timestamp
-struct {
-    __uint(type, BPF_MAP_TYPE_HASH);
-    __type(key, struct request *);
-    __type(value, u64);
-    __uint(max_entries, 1024);
-} start SEC(".maps");
-
-// Attach to kprobe for blk_start_request
-SEC("kprobe/blk_start_request")
-int BPF_KPROBE(trace_start, struct request *req)
-{
-    u64 ts = bpf_ktime_get_ns();
-    bpf_map_update_elem(&start, &req, &ts, BPF_ANY);
-    return 0;
-}
-
-char LICENSE[] SEC("license") = "GPL";

tests/c-form/struct_field_tests.bpf.c

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+/*
+Information gained from reversing this (multiple kernel versions):
+There is no point of
+```llvm
+ tail call void @llvm.dbg.value(metadata ptr %0, metadata !60, metadata !DIExpression()), !dbg !70
+ ```
+ and the first argument of passthrough is fucking useless. It just needs to be a distinct integer:
+ ```llvm
+   %9 = tail call ptr @llvm.bpf.passthrough.p0.p0(i32 3, ptr %8)
+ ```
+*/
+
+SEC("tp/syscalls/sys_enter_execve")
+int handle_setuid_entry(struct trace_event_raw_sys_enter *ctx) {
+  // Access each argument separately with clear variable assignments
+  unsigned long arg0 = ctx->args[0];
+  bpf_printk("args[0]: %u", arg0);
+
+  unsigned long arg1 = ctx->args[1];
+  bpf_printk("args[1]: %u", arg1);
+
+  // Remove the duplicate access to args[1]
+
+  unsigned long arg2 = ctx->args[2];
+  bpf_printk("args[3]: %u", arg2);
+  bpf_printk("args[4]: %u", ctx->args[2]);
+
+  return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";

tests/c-form/xdp_modify.bpf.c

@@ -0,0 +1,21 @@
+// xdp_rewrite.c
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <linux/if_ether.h>
+
+SEC("xdp")
+int xdp_rewrite_mac(struct xdp_md *ctx)
+{
+    void *data_end = (void *)(long)ctx->data_end;
+    void *data     = (void *)(long)ctx->data;
+
+    struct ethhdr *eth = data;
+    if ((void*)(eth + 1) > data_end)
+        return XDP_PASS;
+    __u8 new_src[ETH_ALEN] = {0x02,0x00,0x00,0x00,0x00,0x02};
+    for (int i = 0; i < ETH_ALEN; i++) eth->h_source[i] = new_src[i];
+
+    return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";

tests/failing_tests/vmlinux/struct_field_access.py

@@ -0,0 +1,28 @@
+import logging
+
+from pythonbpf import bpf, section, bpfglobal, compile_to_ir
+from pythonbpf import compile  # noqa: F401
+from vmlinux import TASK_COMM_LEN  # noqa: F401
+from vmlinux import struct_trace_event_raw_sys_enter  # noqa: F401
+from ctypes import c_int64
+
+# from vmlinux import struct_uinput_device
+# from vmlinux import struct_blk_integrity_iter
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: struct_trace_event_raw_sys_enter) -> c_int64:
+    a = 2 + TASK_COMM_LEN + TASK_COMM_LEN
+    print(f"Hello, World{TASK_COMM_LEN} and {a}")
+    return c_int64(TASK_COMM_LEN + 2)
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile_to_ir("struct_field_access.py", "struct_field_access.ll", loglevel=logging.INFO)
+# compile()

tests/passing_tests/vmlinux/simple_struct_test.py

@@ -1,10 +1,26 @@
-from pythonbpf import bpf, section, bpfglobal, compile_to_ir
+import logging
+
+from pythonbpf import bpf, section, bpfglobal, compile_to_ir, map
+from pythonbpf import compile  # noqa: F401
 from vmlinux import TASK_COMM_LEN  # noqa: F401
 from vmlinux import struct_trace_event_raw_sys_enter  # noqa: F401
+from ctypes import c_uint64, c_int32, c_int64
+from pythonbpf.maps import HashMap
 
 # from vmlinux import struct_uinput_device
 # from vmlinux import struct_blk_integrity_iter
-from ctypes import c_int64
+
+
+@bpf
+@map
+def mymap() -> HashMap:
+    return HashMap(key=c_int32, value=c_uint64, max_entries=TASK_COMM_LEN)
+
+
+@bpf
+@map
+def mymap2() -> HashMap:
+    return HashMap(key=c_int32, value=c_uint64, max_entries=18)
 
 
 # Instructions to how to run this program
@@ -16,8 +32,9 @@ from ctypes import c_int64
 @bpf
 @section("tracepoint/syscalls/sys_enter_execve")
 def hello_world(ctx: struct_trace_event_raw_sys_enter) -> c_int64:
-    print("Hello, World!")
-    return c_int64(0)
+    a = 2 + TASK_COMM_LEN + TASK_COMM_LEN
+    print(f"Hello, World{TASK_COMM_LEN} and {a}")
+    return c_int64(TASK_COMM_LEN + 2)
 
 
 @bpf
@@ -26,4 +43,5 @@ def LICENSE() -> str:
     return "GPL"
 
 
-compile_to_ir("simple_struct_test.py", "simple_struct_test.ll")
+compile_to_ir("simple_struct_test.py", "simple_struct_test.ll", loglevel=logging.DEBUG)
+# compile()